Inhibitory effect of oxytocin on plasma neuropeptide Y in humans

Oxytocin does not modify GH, ACTH, cortisol and prolactin responses to Ghrelin in normal men

BACKGROUND

In order to test the possible effect of Oxytocin (OT) on Ghrelin-stimulated GH, PRL, ACTH and cortisol, ten healthy normal men were studied.

TESTS

Ghrelin (0.2 μg/kg body weight (BW)) as an iv bolus; Ghrelin plus OT (2 IU as bolus plus 0.07 IU/min administered for 90 min).

RESULTS

The administration of OT did not change GH, PRL, ACTH and cortisol release induced by Ghrelin.

CONCLUSIONS

The data suggests that in humans OT did not modulate the GH, PRL, ACTH and cortisol response to Ghrelin.

Oxytocin inhibits the stimulatory effect of ghrelin on circulating neuropeptide Y levels in humans

Oxytocin (OT) effect on ghrelin-stimulated neuropeptide Y (NPY) secretion was evaluated in 12 normal men.

TESTS

ghrelin (1 microg/kg B.W. as an intravenous bolus); OT (2 mIU/min infusion); ghrelin plus OT; normal saline. Plasma NPY did not change during saline or OT infusions, whereas it showed a significant 29% increase vs baseline at 15 min after ghrelin injection. When OT was present, ghrelin-induced NPY increment was completely abolished. Results show that oxytocin modulates the NPY response to ghrelin, whereas it is unable to produce direct inhibitions of basal circulating NPY levels.